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DHT22 2 click

PID: MIKROE-2818

Weight:25 g

DHT22 2 click is used for measuring the environmental temperature and relative humidity. It uses the CM2322 sensor, with very accurate thermal and humidity measuring capabilities. It can use either 1-Wire or I2C protocol to communicate with the integrated circuit.

Attributes like the ultra-small size, low power consumption,data signal transmission distance up to 20 meters, make this sensor the perfect choice for all kinds of applications that require measurement of the temperature and humidity.

Table of contents

DHT22 2 click is used for measuring the environmental temperature and relative humidity. It uses the CM2322 sensor, with very accurate thermal and humidity measuring capabilities. It can use either 1-Wire or I2C protocol to communicate with the integrated circuit.

Attributes like the ultra-small size, low power consumption, data signal transmission distance up to 20 meters, make this sensor the perfect choice for all kinds of applications that require measurement of the temperature and humidity.

How does the click work?

The sensor used on this click is CM2322. This sensor contains humidity and temperature measurement elements, compensated and calibrated in the accurate calibration chamber. The calibration coefficient is saved in the OTP memory of an integrated MCU. The integrated MCU also provides I2C or 1-Wire interface, selectable by the onboard SMD jumper selectors. The operating voltage can also be selected by the onboard SMD jumper.

Typical temperature accuracy is ±0.3°C, while relative humidity accuracy is 2% RH, with the resolution of 0.1for both measured properties.

I2C/1-Wire interface is used to communicate with the host MCU, sending the measurement data every 2 seconds. Proprietary data collecting techniques are used to average the sampled values, after which the result is sent via the I2C/1-Wire bus.

Specifications

Type

Temperature / Humidity

On-board modules

CM2322 sensor with very accurate thermal and humidity measuring capabilities

Pinout diagram

This table shows how the pinout on DHT22 2 click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes

Pin

Pin

Notes

NC

1

AN

PWM

16

OW

1-wire

NC

2

RST

INT

15

NC

NC

3

CS

RX

14

NC

NC

4

SCK

TX

13

NC

NC

5

MISO

SCL

12

SCL

I2C clock

NC

6

MOSI

SDA

11

SDA

I2C data

Power supply

+3.3V

7

3.3V

5V

10

+5V

Power supply

Ground

GND

8

GND

GND

9

GND

Ground

DHT22 2 click maximum ratings

Description

Min

Typ

Max

Unit

Logic voltage level

3.3

5

5.5

V

SCL clock frequency

100

kHz

Measuring range (T)

-40

+80

°C

Measuring range (RH)

0%

99%

RH

Onboard settings and indicators

Label

Name

Default

Description

JP1

OW/SCL

Right

Digital interface selection. Left position 1-Wire, right position I2C.

JP2

OW/SDA

Right

Digital interface selection. Left position 1-Wire, right position I2C.

JP3

LOGIC SEL

Left

Logic level voltage selection. Left position 3.3V, right position 5V.

PWR

Power LED

-

Power LED indicates that the click is powered on

Software Support

We provide a library for the DHT22 2 click on our LibStock page, as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Library description

Library contains key functions used to read temperature and humidity data from the DHT22 2 click.

The example uses the library functions to read the temperature and humidity from the sensor and sends the data to the user, via the UART interface. The two functions use I2C interface to communicate with the MCU. Both of these functions return data in floating format, which only needs to be converted to a string with the compiler function FloatToString, before it is sent to the UART module. After that, the temperature and the humidity data can be viewed using the UART terminal.

The full application code, and ready to use projects can be found on our LibStock page.

Other mikroE Libraries used in the example:

UART

I2C

Additional notes and information

Depending on the development board you are using, you may need USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.